Magnetic resonance diffusion tensor imaging (DTI) provides a powerful tool for mapping neural histoarchitecture in vivo. However, DTI can only resolve a single fiber orientation within each imaging voxel due to the constraints of the tensor model. For example, DTI cannot resolve fibers crossing, bending, or twisting within an individual voxel. Intravoxel fiber crossing can be resolved using q-s...

We propose a new information-theoretic metric, the symmetric Kullback-Leibler divergence (sKL-divergence), to measure the difference between two water diffusivity profiles in high angular resolution diffusion imaging (HARDI). Water diffusivity profiles are modeled as probability density functions on the unit sphere, and the sKL-divergence is computed from a spherical harmonic series, which grea...

Diffusion-weighted magnetic resonance imaging holds substantial promise as a technique for non-invasive imaging of white matter (WM) axonal projections. For diffusion imaging to be capable of providing new insight into the connectional neuroanatomy of the human brain, it will be necessary to histologically validate the technique against established tracer methods such as horseradish peroxidase ...

Introduction: Multi-subject tractography in Diffusion-Weighted MRI is a valuable technique for statistical analysis of the brain‟s anatomical connectivity and population studies (e.g., Leemans et al. 2006; Voineskos et al. 2008; Jbabdi et al. 2009). Prior approaches are based on the post processing of tractography results from individual subjects, and generally require aligning the tracts and m...

We generalize the Gaussian multi-resolution image paradigm for a Euclidean domain to general Riemannian base manifolds and also account for the codomain by considering the extension into a fibre bundle structure. We elaborate on aspects of parametrization and gauge, as these are important in practical applications. We subsequently scrutinize two examples that are of interest in bio-mathematical...

High angular resolution diffusion imaging (HARDI) captures the angular diffusion pattern of water molecules more accurately than diffusion tensor imaging (DTI). This is of importance mainly in areas of complex intra-voxel fiber configurations. However, the extra complexity of HARDI models has many disadvantages that make it unattractive for clinical applications. One of the main drawbacks is th...

Number: 979 Submitted By: Ming-Chang Chiang Last Modified: January 5 2008 MAPPING GENETIC INFLUENCES ON BRAIN FIBER ARCHITECTURE WITH HIGH ANGULAR RESOLUTION DIFFUSION IMAGING (HARDI) Ming-Chang Chiang1, Marina Barysheva1, Agatha D. Lee1, Sarah Madsen1, Andrea D. Klunder1, Arthur W. Toga1, Katie L. McMahon2, Greig I. de Zubicaray2, Matthew Meredith2, Margaret J. Wright3, Anuj Srivastava4, Nikol...

High Angular Resolution Imaging (HARDI) can better explore the complex micro-structure of white matter compared to Diffusion Tensor Imaging (DTI). Orientation Distribution Function (ODF) in HARDI is used to describe the probability of the fiber direction. There are two type definitions of the ODF, which were respectively proposed in Q-Ball Imaging (QBI) and Diffusion Spectrum Imaging (DSI). Som...

Diffusion weighted imaging (DWI) can reveal the orientation of the underlying fiber populations in the brain. High angular resolution diffusion imaging (HARDI) is increasingly used to better resolve the orientation and mixing of fibers. Here, we assessed the added value of multi-shell q-space sampling on the reconstruction of major fibers using mathematical frameworks from q-ball imaging (QBI) ...

Introduction: During the late fetal period and early preterm period, the most prominent transient layer is the subplate (SP) zone, located between the immature cortex (cortical plate; CP) and the immature white matter (intermediate zone; IZ), which contains awaiting thalamo-cortical afferent fibers that cross one another [1-3]. The SP is especially thick in humans which develops around prenatal...